Bundle put and get Unit test

I'm trying to make a test that will verify that a value is successfully written on a Bundle.

This is a simple class that will write a boolean value on a Bundle:

public class Coder {
    public void serialize(Bundle bundle, String key, boolean value) {
        bundle.putBoolean(key, value);
    }
}

I want to test the serialize method checking the Bundle passed as parameter after the method call using bundle.getBoolean(String).

I tried with an ArgumentCaptor without success:

Coder coder = mock(Coder.class);
Bundle bundle = mock(Bundle.class);

ArgumentCaptor<Bundle> bundleCaptor = ArgumentCaptor.forClass(Bundle.class);
coder.serialize(bundle, key, expectedValue);
verify(coder).serialize(bundleCaptor.capture(), eq(key), eq(expectedValue));

Bundle mockBundle = bundleCaptor.getValue();
assertEquals(expectedValue, mockBundle.getBoolean(key));

But mockBundle.getBoolean(key) returns false